The Formulations Core (Core B) will provide preformulation, formulation development, and formulation assessment efforts in direct support of Projects 1, 2, 3, &4. Within the scope of this program Core B will develop a novel delivery system utilizing a pellet technology developed by Auritec Pharmaceuticals. This technology will be developed for the fusion inhibitor RC-101 and the non nucleoside reverse transcriptase inhibitor CSIC both individually and in combination. Each of these drug candidates has hurdles to overcome to develop them into drug products. RC-101 is a hydrophilic peptide drug candidate while CSIC is hydrophobic in nature. The use of the pellet technology allows for co-delivery of these two very dissimilar drug candidates in a single product. For delivery to the vagina the pellets are inserted into a vaginal ring device. This drug delivery system will provide sustained release of both drug candidates offering a coitally independent drug product. We anticipate initially developing a drug product which will consistently deliver drug over a period of one month. Within the core, preformulation data on each of the drug candidates will initially be developed. This data will be used to successfully formulate the drug candidates. The pellet formulation effort will occur at Auritec Pharmaceuticals and the vaginal rings will be developed by Dr. Patrick Kiser at the University of Utah. Dr. Kiser additionally has the needed technology available to him to manufacture vaginal rings of appropriate size for use in macaque studies which will be necessary for successful completion of studies planned within this program. Preformulation assessments as well as pharmaceutical product assessments will be conducted by Dr. Lisa Rohan at the University of Pittsburgh. She will also coordinate the efforts of the three groups toward drug delivery system design and development. In addition within her group a secondary drug delivery platform (quick dissolve film) will be developed for these agents. The core will interact with Projects 1, 2, and 3 on an iterative basis throughout the drug product development stages and will ultimately provide drug product for use in macaque safety and efficacy studies being conducted in Project 4.